Distribution: S - Camp (Jatta 1909-1911), Si (Jatta 1909-1911).
Description: Thallus crustose, very thin, continuous to somehow granular and uneven, pale to dirty grey-green or white. Apothecia lecanorine at least when young, round, adpressed, emergent to sessile, 0.2-0.4 mm across, with an orange-brown to dark brown, flat to finally convex disc (translucent and dark-spotted when wet), and a rather thin, smooth to crenulate, often finally excluded, white or pale grey thalline margin. Proper margin thin, dark brown; epithecium pale brown, often with fine pigment granules; hymenium colourless, 45-65 µm high; paraphyses coherent, simple, 1.5-2 µm thick at base, the apical cells pale to dark brown, 2-3(-4) µm wide; hypothecium colourless. Asci 10-16-spored, clavate or inflated-clavate, with a K/I+ blue apical dome penetrated by a narrow, K/I- apical cushion surrounded by a narrow, deeply K/I+ blue zone, the wall K/I- but surrounded by an I+ red-brown, K/I+ blue outer layer, the ocular chamber relatively small, Biatora-type. Ascospores 1-septate hyaline, narrowly ellipsoid, oblong to almost fusiform, 10-14 x 3-4 µm. Pycnidia rare, immersed, the wall pale brown in upper part, colourless below. Microconidia thread-like, curved. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: this species appears to prefer lichen-rich communities on old deciduous trees with rough, base-rich bark, such as Sambucus, Populus, and Salix. It is probably widespread throughout Europe, but very likely overlooked or mistaken for L. cyrtella, with which it has been often synonymised. For further details see Reese Næsborg (2008).